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<head><meta charset="utf-8"><title>Symbol demangling or polymorphization? · general · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/index.html">general</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html">Symbol demangling or polymorphization?</a></h3>

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<a name="231240348"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231240348" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> The 8472 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231240348">(Mar 21 2021 at 20:53)</a>:</h4>
<p>When I see a symbol like this in objdump output:</p>
<div class="codehilite" data-code-language="Rust"><pre><span></span><code><span class="o">&lt;</span><span class="n">alloc</span>::<span class="n">vec</span>::<span class="n">source_iter_marker</span>::<span class="o">&lt;</span><span class="k">impl</span><span class="w"> </span><span class="n">alloc</span>::<span class="n">vec</span>::<span class="n">spec_from_iter</span>::<span class="n">SpecFromIter</span><span class="o">&lt;</span><span class="n">T</span><span class="p">,</span><span class="n">I</span><span class="o">&gt;</span><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">alloc</span>::<span class="n">vec</span>::<span class="nb">Vec</span><span class="o">&lt;</span><span class="n">T</span><span class="o">&gt;&gt;</span>::<span class="n">from_iter</span><span class="o">&gt;</span><span class="w"></span>
</code></pre></div>
<p>does that mean <code>T</code> and <code>I</code> are not used in the body and thus the function has been polymorphized or does the symbol mangling  omit generics  now?</p>



<a name="231240819"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231240819" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tm <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231240819">(Mar 21 2021 at 21:01)</a>:</h4>
<p>Legacy mangling doesn't include type parameters, you would need <code>-Z symbol-mangling-version=v0</code> for that.</p>



<a name="231240998"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231240998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> The 8472 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231240998">(Mar 21 2021 at 21:04)</a>:</h4>
<p>I could have sworn I saw the type parameters filled in before</p>



<a name="231241884"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231241884" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> tm <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231241884">(Mar 21 2021 at 21:20)</a>:</h4>
<p>maybe from debuginfo? They should be included there.</p>



<a name="231243337"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231243337" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> The 8472 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231243337">(Mar 21 2021 at 21:48)</a>:</h4>
<p>yeah, that might be it, I just disabled that to test something</p>



<a name="231246836"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/Symbol%20demangling%20or%20polymorphization%3F/near/231246836" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> davidtwco <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/Symbol.20demangling.20or.20polymorphization.3F.html#231246836">(Mar 21 2021 at 22:57)</a>:</h4>
<p>Polymorphization is disabled by default, so unless you've enabled it, it isn't that.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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